1. Technical Field
The present invention relates to inkjet ink and an ink cartridge, an ink jet recording device, and inkjet printed matter that use the inkjet ink.
2. Background Art
Inkjet printers are widely used due to their advantages such as low noise and low running costs, and many printers capable of printing color images on plain paper are now widely available on market.
However, it is extremely difficult to satisfy all the properties required of images produced using such printers, such as good color reproducibility, abrasion resistance, durability, light resistance, drying property, feathering, color bleed, duplex printing, and ink discharging stability. As a result, the ink used is selected based on the particular application.
In general, the ink used in inkjet recording is mainly composed of water, with a colorant and a hydrosoluble solvent such as glycerin added to prevent clogging.
As the colorant, dyes are widely used for their coloring and stability. However, the light resistance and water resistance of images produced using such dye-based ink are inferior. Water resistance can be improved in some degree by using specialized recording media having an ink absorbing layer, but is not satisfactory at all when it comes to plain paper.
To compensate for such defects, ink using a pigment as a colorant (pigment ink) has begun to be widely used.
Although pigment ink is successful and superior to dye ink with regard to light resistance, water resistance, etc., the coloring of the pigment ink is degraded by coherence of beams of light having different wavelengths and phases produced by multiple reflections of the beams of light within the pigment. For this reason, pigment ink is considered to be inferior to dye ink in general with regard to the coloring.
In an attempt to compensate for such degradation of the coloring of the pigment ink, pigment particulates that are coated with a resin are used.
By this coating, the fixability and the gas resistance of the pigment ink are further improved and the dispersion stability thereof also ameliorates.
However, currently, even such pigment ink is not still on a par with dye ink with regard to gloss.
In addition, JP-2003-003110-A describes quality recording with a high color density exhibiting fineness and high saturation by using a pseudo-unidimensional crystalline organic color pigment as a colorant, which has an X-ray diffraction spectrum having a diffraction line showing the maximum intensity and its n-th order (“n” is an integer of 2 or greater) diffraction lines as main peaks.